In electrophotographic and electrostatic recording processes, developer is used to visualize an electrostatic image or an electrostatic latent image. Developers can be classified broadly into two types: a two-component developer including toner and carrier particles; and a one-component developer exclusively of toner. One-component developers can be further classified into magnetic one-component developers and nonmagnetic one-component developers. To increase the fluidity of toner, a fluidizing agent such as colloidal silica is often independently added to nonmagnetic one-component developers. Typically, toner includes coloring particles obtained by dispersing a colorant such as carbon black or other additives in a latex.
Methods for preparing toner include pulverization and polymerization processes. In pulverization processes, toner is obtained by melting and mixing a synthetic resin with a colorant and, if required, other additives; pulverizing the mixture; and sorting the particles until particles of desired size are obtained. In polymerization processes, a polymerizable monomer composition is manufactured by uniformly dissolving or dispersing various additives, such as a colorant, a polymerization initiator and, if required, a cross-linking agent and an antistatic agent, in a polymerizable monomer. The polymerizable monomer composition may be dispersed in an aqueous dispersive medium, which includes a dispersion stabilizer, using an agitator to shape the minute liquid droplet particles. Subsequently, the temperature of the dispersion may be increased, and suspension polymerization is performed to obtain polymerized toner having coloring polymer particles of a desired size.
Conventionally, toner used in an imaging apparatus is obtained through a pulverization process. However, during pulverization, it may be difficult to precisely control the particle size, geometric size distribution, and structure of toner, and it may thus also be difficult to separately control the major characteristics of toner, such as charging characteristics, fixability, flowability, and preservation characteristics.
Polymerized toner processes have drawn increasing attention due to the ease of controlling the size of the particles, and for not requiring complex manufacturing processes such as sorting. When toner is prepared through a polymerization process, polymerized toner having a desired particle size and particle size distribution may be obtained without pulverizing or sorting.
Conventionally, when polymerized toner is manufactured, styrene and acrylate copolymers are used as the binder resin. However, as color toner is used in a wider range of applications, more transparent resins may be required. In addition, as an awareness of environmental issues increases, lower energy and more environmentally friendly processes are often being required. Improved electrographic toner and methods for preparing the same are thus desirable.